1. Field of the Invention
The present invention relates generally to error amplifiers and more particularly to error amplifiers for use in voltage boosting circuits such as negative switching regulators and charge pumps.
2. Description of the Related Art
Error amplifiers are configured to provide an error signal in response to the difference between an operational signal (e.g., a feedback signal) and a reference signal. They are especially suited for use in feedback systems that control an output signal to have a desired correspondence to a reference.
Exemplary feedback systems are negative switching regulators that are powered by a supply voltage and provide a controlled output voltage with a polarity opposite that of the supply voltage. Error amplifiers for such systems have generally included an input stage, a gain stage, and an output stage. The input stage is typically configured to symmetrically compare signals at a pair of input nodes to thereby generate a difference signal. The gain stage provides a single-ended error signal with gained response to the difference signal and the output stage provides buffering while delivering the error signal to a system port.
Although such error amplifiers can be configured to provide excellent performance, they typically have a number of disadvantages that limit their use in integrated circuits, e.g., they are complex, expensive, and require large compensation capacitors.